304
FXUS01 KWBC 172004
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
404 PM EDT THU SEP 17 2009
VALID 00Z FRI SEP 18 2009 - 12Z SAT SEP 19 2009
CONCLUDING THE WORK WEEK AND ENTERING THE WEEKEND...NO SIGNIFICANT
CHANGES ARE EXPECTED AS THE UPPER-LEVEL PATTERN HOLDS STEADY WITH
A PROGRESSIVE FLOW ACROSS CANADA AND A PAIR OF CUT-OFF SYSTEMS
AFFECTING THE SOUTHERN HALF OF THE U.S. MEANWHILE...A STRONG UPPER
RIDGE EXTENDING NORTHWARD INTO SASKATCHEWAN HAS BROUGHT LATE
SUMMER/EARLY AUTUMN WARMTH TO THE NORTHERN TIER STATES AND INTO
CANADA. IN FACT...CURRENT SURFACE OBSERVATIONS ACROSS SOUTHERN
SASKATCHEWAN INDICATED WIDESPREAD MID TO UPPER 80S OVER THE REGION
WHICH IS A SIGNIFICANT DEPARTURE FROM CLIMATOLOGY.
AN UPPER-LEVEL LOW ACROSS THE LOWER MISSISSIPPI VALLEY WILL
CONTINUE BRINGING SHOWERS AND THUNDERSTORMS TO MUCH OF THE
SOUTHERN U.S. INTO THE WEEKEND. THIS FEATURE HAS SEEMINGLY HUNG
AROUND FOR NEARLY A WEEK CREATING A FLOODING THREAT ACROSS THE
REGION. CURRENTLY A VARIETY OF FLOOD-RELATED WATCHES AND WARNINGS
ARE IN EFFECT ACROSS THE LOWER MISSISSIPPI VALLEY AND INTO THE
TENNESSEE RIVER VALLEY. AS THE LOW PRESSURE CENTER ALOFT GRADUALLY
DRIFTS EASTWARD AND WEAKENS...THE RAINFALL SHOULD BECOME MORE
DISORGANIZED AND SCATTERED IN NATURE. BUT GIVEN THIS PORTION OF
THE NATION HAS BEEN RECEIVING RAINFALL DAILY FOR ALMOST A WHOLE
WEEK...FLOODING WILL CONTINUE TO BE AN ISSUE...ESPECIALLY FROM
SOUTHEASTERN ARKANSAS AND STRETCHING INTO CENTRAL TENNESSEE.
LIKE ITS COUNTERPART ACROSS THE DEEP SOUTH...ANOTHER UPPER LOW
CENTER LOCATED OVER THE FOUR CORNERS REGION WILL GRADUALLY WEAKEN
AS THE WEEKEND APPROACHES. SHOWERS AND THUNDERSTORMS WILL CONTINUE
ACROSS MUCH OF NEW MEXICO THROUGH FRIDAY BEFORE THE THREAT
SUBSIDES BY THE WEEKEND.
LOOKING AT THE NORTHERN STREAM...A MUCH MORE PROGRESSIVE PATTERN
WILL BE IN PLACE FEATURING A SERIES OF WEATHER SYSTEMS WHICH WILL
PRIMARILY AFFECT CANADA. HOWEVER...UPPER TROUGHS PUSHING THROUGH
THE PACIFIC NORTHWEST AND NORTHEASTERN U.S...RESPECTIVELY...WILL
BRING A SHOT OF RAIN SHOWERS TO EACH OF THESE REGIONS. THE MORE
IMPRESSIVE OF THE TWO SYSTEMS IS THE ONE CURRENTLY BRINGING
MODERATE TO HEAVY RAINFALL TO COASTAL BRITISH COLUMBIA. PLENTY OF
MOISTURE WILL FEED THIS SYSTEM AS A STRONG ONSHORE FLOW PERSISTS
OFF THE EASTERN PACIFIC WATERS. MEANWHILE...ACROSS THE NEW ENGLAND
STATES...EXPECT SCATTERED RAIN SHOWERS FOR FRIDAY UPON FRONTAL
PASSAGE BEFORE A DOME OF HIGH PRESSURE SETTLES IN FOR THE WEEKEND.
RUBIN-OSTER
GRAPHICS AVAILABLE AT WWW.HPC.NCEP.NOAA.GOV
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page